Insight into the Impacts of Heat Treatment on Microstructure and Mechanical Properties of TC11 Titanium Alloy

The effect of heat treatment on the microstructure and mechanical properties of TC11 titanium alloy were investigated. The α phase begins to transform to the β phase at 950 °C, and the α phase has almost completely transformed to the β phase at 1100 °C. After the alloy aging tread, the fine secondary alpha phase becomes more abundant. The cycle heat treatment results show that the strength of the alloy decreases, and its plasticity and toughness increase as the number of cycle heat treatments increases. This is due to the gradual increase in the number of needle-like secondary α phases interspersed at the α phase interface impedes slip. The ultra-high circumferential fatigue results show that the ultra-high fatigue strength at 10⁹ cycles for a failure probability of 50% (σ⁹(10)) was calculated as 690 Mpa. In summary, the fatigue life of the TC11 alloy can exceed 10⁹.